1. Field of the Invention
The present invention relates to a wavelength-multiplexing connector, an optical transmission device, and an optical communication system. More particularly, the present invention relates to a wavelength-multiplexing connector enabling a conventional duplex-fiber transceiver to be easily adapted for use in a single-fiber duplex communication system.
2. Description of the Related Art
FIG. 7 shows a currently used optical transceiver. The transceiver of FIG. 7 has a simple construction for performing single-wavelength transmitting/receiving through a couple of optical fibers 50. Each transceiver 1, 2 comprises a laser-diode LD, a driving-circuit 61 for the LD, a photodiode PD, and a receiving-circuit 62 for the PD. The transceiver has an outer structure in which a receiving receptacle 63 and a transmitting receptacle 64 for connection with optical fibers are projected from a package formed by resin molding as shown in FIG. 8. Most of currently used transceivers are of the above-mentioned type and are employed as optical data links in a 0.8-0.9 μm wavelength band and a 1.3-1.5 μm wavelength band, for example, in many cases.
On the other hand, as shown in FIG. 9, an optical transmission device capable of performing transmitting/receiving at the same time through a single fiber has been developed for more effective use of optical fibers. The optical transmission device has a function of separating a transmitting-signal and a receiving-signal from each other by using a wavelength-separator 65 and a mirror 66. For example, a transceiver 1 transmits a wavelength-signal of 1.3 μm and receives a wavelength-signal of 1.5 μm. A transceiver 2 transmits and receives those wavelength-signals in a reversed manner.
Such an optical transmission device mainly comprises, as shown in FIG. 10, a light waveguide 80, a wavelength division multiplexing (WDM) filter 81, an optical emitting device 82, and an optical receiving device 83. Those components are constituted as an integral unit (see Japanese Unexamined Patent Application Publication No. 11-202140). The WDM filter 81 shown in FIG. 10 has also the functions of the wavelength-separator 65 and the mirror 66 both shown in FIG. 9.